You can easily look and confirm this. The current central valley part of the project is mostly grade separation projects. There is something like 30 of them. No

You can easily look and confirm this. The current central valley part of the project is mostly grade separation projects. There is something like 30 of them. Not including a half dozen really major projects. Either where the line goes through a city, crosses a river, or over an existing rail line. My take is there are a bunch of reasons to build the thing. None of them on their own is convincing but taken together it's reasonable. Things like. All the major airports in California are maxed out and expanding them would be near impossible or very expensive. You can look at costs to do that in non US countries. I think $15 billion for two runways at Heathrow. Imagine doing that times six. Growing population in the central valley makes the current at grade rail crossings untenable. Distinct lack of high speed commuter rail in the major metro's.